The present invention relates to a polishing agent for processing semiconductor, a dispersant used therefor, and a process for preparing a semiconductor device using the above polishing agent for processing the semiconductor.
In accordance with advance in high-performance and multi-layering for semiconductor devices, flattening technology for uneven plane form became inevitable. It has promoted technological development for the flattening of an SiO2 insulating film, a metal film such as Al, W, Cu, Ru or Ta, and a conductive film such as poly-Si, which are formed by means of plasma CVD, constant pressure CVD, thermal oxidation and the like. And there has been developed a polishing agent, a polishing device and a process employed therefor.
Generally, a polishing device comprises a mechanism that a polishing board laminated with a polishing pat and a polishing substrate are supported and the rotating substrate is pressed to the polishing pat, and a mechanism that a polishing agent is supplied.
As to polishing agent supply, various supplying methods are known. For example, by using a polishing particle nozzle, a dispersant nozzle and a pure water nozzle, the polishing particles are supplied with the water through the polishing particle nozzle, while the dispersant is supplied with the water through the dispersant nozzle. Also, all elements can be previously prepared to supply the prepared polishing agent from a single nozzle.
This is because the most suitable mixing ratios among the polishing particles, the dispersant and the pure water vary depending on the processed material, and because it is aimed to polish by flexibly varying the mixing ratio depending on the kinds of the processed material.
As to the polishing agent, there is generally used a silica polishing agent, a ceria polishing agent and an alumina polishing agent.
The silica polishing agent is produced by dispersing fumed or colloidal silica in water and by suitably arranging pH thereof with KOH, ammonium and the like. The ceria polishing agent is prepared by dispersing polishing particle of ceria in water, while the alumina polishing agent is prepared by dispersing alumina in water.
In general, a polishing agent contains a dispersant. For example, Japanese Unexamined Patent Publication No. 17195/2000 discloses that ammonium salt of polyacrylate is used as a dispersant.
However, since the above conventional polishing agent includes the above dispersant, there have been problems that the dispersion is unsatisfactory, the polishing particles are coagulated and easily sedimentated to generate polishing flaw, and thereby stability and re-productivity cannot be achieved in polishing.
The present invention is carried out in order to solve these problems. The object of the present invention is to provide a polishing agent for processing semiconductor which can control coagulation and sedimentation and has stable and re-productive polishing properties under a proper dispersing condition to prevent generation of polishing flaw; a dispersant used therefor; and a process for preparing a semiconductor device using the same.
The first dispersant used for a polishing agent for processing semiconductor of the present invention comprises a dispersant component comprising a compound having glucose structure, and water.
The second dispersant used for a polishing agent for processing semiconductor of the present invention comprises a dispersant component and water, wherein the polishing dispersant component is at least one selected from the group consisting of gelatin, taragum, cationic guar gum, collagen, dextrin, tragacanth, propylene glycol alginate, cyclodextrin, chitin, hyaluronic acid, carmelose, starch, cyprogum, bee gum, pullulan, laponite, pectin, bentonite, trehalose, casein, saccharose, maltose, fructose, mannose, glucuronic acid, glucosamine, glucosan, cationic cellulose, glucosidase, glucose phenylosazone, hydroxyethylcellulose, chitosan, starch phosphate, soybean lecithin, xanthan gum, tamalind gum, locust bean gum, tamalindsy gum, Arabic gum, cyliumseed gum, caragynan, gelan gum, guar gum and polyglycerol fatty acid ester.
The first polishing agent for processing semiconductor of the present invention comprises the above first dispersant and polishing particles.
The second polishing agent for processing semiconductor of the present invention comprises the above second dispersant and polishing particles.
The third polishing agent for processing semiconductor of the present invention is that in the above first polishing agent, the polishing particles is at least one selected from the group consisting of cerium oxide, silica, silica sol and alumina, whose particle size of the primary particles is at most 1 xcexcm.
The fourth polishing agent for processing semiconductor of the present invention is that in the above second polishing agent, the polishing particles is at least one selected from the group consisting of cerium oxide, silica, silica sol and alumina, whose particle size of the primary particles is at most 1 xcexcm.
The fifth polishing agent for processing semiconductor of the present invention comprises a first solution prepared by dispersing polishing particles in water and a second solution of the above first dispersant used for the polishing agent for the semiconductor.
The sixth polishing agent for processing semiconductor of the present invention comprises a first solution prepared by dispersing polishing particles in water and a second solution of the above second dispersant used for the polishing agent for the semiconductor.
The first process for preparing a semiconductor device is that polishing is carried out by supplying the first polishing agent for the semiconductor to a polished film which is formed on a semiconductor substrate.
The second process for preparing a semiconductor device is that polishing is carried out by supplying the second polishing agent for the semiconductor to a polished film which is formed on a semiconductor substrate.